Dounreay reduces radioactivity levels

“Significant progress” has been made to destroy one of the most hazardous legacies of Britain’s nuclear research programme from the 20th century, according to the Nuclear Decommissioning Authority (NDA).

A clean-up operation funded by the NDA has destroyed more than half the liquid metal used as coolant in the experimental Dounreay Fast Reactor.

Its annual report published today describes the toxic sodium-potassium alloy it inherited in 2005 as the second biggest hazard in its £3bn-a-year clean-up mission.

Some 57,000 litres remained inside the reactor when its decommissioning stalled in the 1980s.

A purpose-built chemical treatment plant commissioned by the NDA in 2009 has now destroyed more than half of it.

The metal is so radioactive that its removal is bringing down radiation levels inside the reactor at a rate of 20 million becquerels a second.

The two-stage process involves chemical conversion and radiological decontamination to produce a salty water that is safe to discharge to sea.

Designers thought the plant could decontaminate the metal by a factor of up to 1000.

But clean-up rates of up to 4M have been achieved and the levels of radioactivity in the effluent are now at the limits of detection.

Millions of pounds in funding from the government’s Industrial Strategy is being set aside for British robotics experts to develop tiny robots capable of operating and repairing pipework from the inside.

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